• Title/Summary/Keyword: Hunan province

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Vibration control of a stay cable with a rotary electromagnetic inertial mass damper

  • Wang, Zhi Hao;Xu, Yan Wei;Gao, Hui;Chen, Zheng Qing;Xu, Kai;Zhao, Shun Bo
    • Smart Structures and Systems
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    • v.23 no.6
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    • pp.627-639
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    • 2019
  • Passive control may not provide enough damping for a stay cable since the control devices are often restricted to a low location level. In order to enhance control performance of conventional passive dampers, a new type of damper integrated with a rotary electromagnetic damper providing variable damping force and a flywheel serving as an inertial mass, called the rotary electromagnetic inertial mass damper (REIMD), is presented for suppressing the cable vibrations in this paper. The mechanical model of the REIMD is theoretically derived according to generation mechanisms of the damping force and the inertial force, and further validated by performance tests. General dynamic characteristics of an idealized taut cable with a REIMD installed close to the cable end are theoretically investigated, and parametric analysis are then conducted to investigate the effects of inertial mass and damping coefficient on vibration control performance. Finally, vibration control tests on a scaled cable model with a REIMD are performed to further verify mitigation performance through the first two modal additional damping ratios of the cable. Both the theoretical and experimental results show that control performance of the cable with the REIMD are much better than those of conventional passive viscous dampers, which mainly attributes to the increment of the damper displacement due to the inertial mass induced negative stiffness effects of the REIMD. Moreover, it is concluded that both inertial mass and damping coefficient of an optimum REIMD will decrease with the increase of the mode order of the cable, and oversize inertial mass may lead to negative effect on the control performance.

Understanding the functionality of the rumen microbiota: searching for better opportunities for rumen microbial manipulation

  • Wenlingli Qi;Ming-Yuan Xue;Ming-Hui Jia;Shuxian Zhang;Qiongxian Yan;Hui-Zeng Sun
    • Animal Bioscience
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    • v.37 no.2_spc
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    • pp.370-384
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    • 2024
  • Rumen microbiota play a central role in the digestive process of ruminants. Their remarkable ability to break down complex plant fibers and proteins, converting them into essential organic compounds that provide animals with energy and nutrition. Research on rumen microbiota not only contributes to improving animal production performance and enhancing feed utilization efficiency but also holds the potential to reduce methane emissions and environmental impact. Nevertheless, studies on rumen microbiota face numerous challenges, including complexity, difficulties in cultivation, and obstacles in functional analysis. This review provides an overview of microbial species involved in the degradation of macromolecules, the fermentation processes, and methane production in the rumen, all based on cultivation methods. Additionally, the review introduces the applications, advantages, and limitations of emerging omics technologies such as metagenomics, meta-transcriptomics, metaproteomics, and metabolomics, in investigating the functionality of rumen microbiota. Finally, the article offers a forward-looking perspective on the new horizons and technologies in the field of rumen microbiota functional research. These emerging technologies, with continuous refinement and mutual complementation, have deepened our understanding of rumen microbiota functionality, thereby enabling effective manipulation of the rumen microbial community.

Dynamic stability and structural improvement of vibrating electrically curved composite screen subjected to spherical impactor: Finite element and analytical methods

  • Xiao, Caiyuan;Zhang, Guiju
    • Steel and Composite Structures
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    • v.43 no.5
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    • pp.533-552
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    • 2022
  • The current article deals with the dynamic stability, and structural improvement of vibrating electrically curved screen on the viscoelastic substrate. By considering optimum value for radius curvature of the electrically curved screen, the structure improvement of the system occurs. For modeling the electrically system, the Maxwell's' equation is developed. Hertz contact model in employed to obtain contact forces between impactor and structure. Moreover, variational methods and nonlinear von Kármán model are used to derive boundary conditions (BCs) and nonlinear governing equations of the vibrating electrically curved screen. Galerkin and Multiple scales solution approach are coupled to solve the nonlinear set of governing equations of the vibrating electrically curved screen. Along with the analytical solution, 3D finite element simulation via ABAQUS package is provided with the aid of a FE package for simulating the current system's response. The results are categorized in 3 different sections. First, effects of geometrical and material parameters on the vibrational performance and stability of the curves panel. Second, physical properties of the impactor are taken in to account and their effect on the absorbed energy and velocity profile of the impactor are presented. Finally, effect of the radius and initial velocity on the mode shapes of the current structure is demonstrated.

RSA vs DEM in view of particle packing-related properties of cementitious materials

  • Li, Kai;Stroeven, Piet
    • Computers and Concrete
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    • v.22 no.1
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    • pp.83-91
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    • 2018
  • Various systems for simulating particulate matter are developed and used in concrete technology for producing virtual cementitious materials on the different levels of the microstructure. Basically, the systems can be classified as two distinct families, namely random sequential addition systems (RSAs) and discrete element methods (DEMs). The first type is hardly being used for this purpose outside concrete technology, but became popular among concrete technologists. Hence, it is of utmost relevance to compare the two families in their capabilities, so that the reliability of produced data can be estimated. This paper pursues to do this on the basis of earlier published material of work performed by a succession of PhD students in the group of the second author. Limited references will be given to external sources.

The Power Analysis and Its Control of Two-phase Orthogonal Power Supply for the Continuous Casting

  • Ma, Fujun;Luo, An;Xiong, Qiaopo
    • Journal of Electrical Engineering and Technology
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    • v.10 no.3
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    • pp.971-982
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    • 2015
  • In order to improve the quality of the billet continuous casting, a two-phase orthogonal power supply (TPOPS) for electromagnetic stirrer is researched, which is composed of three-phase PWM rectifier and three-leg inverter. According to the power analysis of system, the ripple of dc-link voltage is analyzed and its analytical expression is derived. In order to improve the performance of electromagnetic stirring, an integrated control method with feedforward control is proposed for PWM rectifier to suppress the fluctuations of dc-link voltage and provide a stable dc source for inverter. According to the simplified equivalent model, a composite current control method is proposed for inverter. This proposed method can combine the merits of feedforward control with feedback control to effectively improve the dynamic output performance of TPOPS. Finally, a 300kVA prototype of TPOPS is developed, and the results have verified the analysis and control method.

The Impacts of Childhood Trauma on Psychosocial Features in a Chinese Sample of Young Adults

  • Wang, Dandan;Lu, Shaojia;Gao, Weijia;Wei, Zhaoguo;Duan, Jinfeng;Hu, Shaohua;Huang, Manli;Xu, Yi;Li, Lingjiang
    • Psychiatry investigation
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    • v.15 no.11
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    • pp.1046-1052
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    • 2018
  • Objective The aims of the present study were to explore the occurrence of childhood trauma and importantly to determine the impacts of childhood trauma on psychosocial features in a Chinese sample of young adults. Methods A survey was carried out in a group of 555 university students by using Childhood Trauma Questionnaire (CTQ), Self-rating Depression Scale (SDS), Self-rating Anxiety Scale (SAS), Dysfunctional Attitudes Questionnaire (DAS), Eysenck Personality Questionnaire (EPQ), and Social Support Rating Scale (SSRS). The moderate-severe cut-off scores for CTQ were used to calculate the prevalence of childhood trauma, and then psychosocial features were compared between individuals with and without childhood trauma. Results A proportion of 18.6% of university students had self-reported childhood trauma exposures. Subjects with childhood trauma reported higher scores of SDS, SAS, DAS, and psychoticism and neuroticism dimensions of EPQ (t=4.311-5.551, p<0.001); while lower scores of SSRS and extraversion dimension of EPQ (t=-4.061- -3.039, p<0.01). Regression analyses further revealed that scores of SAS and DAS were positively (Adjusted B=0.211-0.230, p<0.05), while scores of SSRS were negatively (Adjusted B=-0.273- -0.240, p<0.05) associated with specific CTQ scores. Conclusion Childhood trauma is still a common social and psychological problem. Individuals with childhood trauma show much more depression, anxiety, distorted cognition, personality deficits, and lower levels of social support, which may represent the social and psychological vulnerability for developing psychiatric disorders after childhood trauma experiences.

Comparison of Rice Growth under Subtropical and Temperate Environments (아열대와 온대 기후 하에서 벼 생육 비교)

  • Park H.K.;Xu Migging;Lee K.B.;Choil W.Y.;Choil M.G.;Kim S.S.;Kim C.K.
    • Korean Journal of Agricultural and Forest Meteorology
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    • v.8 no.2
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    • pp.45-53
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    • 2006
  • The objectives of this study are to determine the primary yield components responsible for yield differences in a subtropical environment of the Hunan province China and in a temperature environment of Honam province Korea. Field experiments were conducted in a subtropical environment in Hunan province China during 2002 and in a temperate environment in Honam province Korea during 2003. Seven rice cultivars were grown under optimum crop management in each experiment field. Yield, yield components and plant dry matter were determined at maturation. The highest yield (567 kg/10a) was produced at Honam province by Jinyou 207, a Chinese cultivar, The maximum yield at Hunan province was 453 kg/10a by Sanyou 63. On the average across cultivars, Honam produced 23% greater yields than Hunan. Sink size (spikelets per $m^2$) was responsible far these yield differences. Panicle number per $m^2$ was much greater at Honam.

Effect of a microbial phytase on growth performance, plasma parameters and apparent ileal amino acid digestibility in Youxian Sheldrake fed a low-phosphorus corn-soybean diet

  • He, Shaoping;Medrano, R.F.;Yu, Qifang;Cai, Yixin;Dai, Qiuzhong;He, Jianhua
    • Asian-Australasian Journal of Animal Sciences
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    • v.30 no.10
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    • pp.1442-1449
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    • 2017
  • Objective: This study investigated the effect of microbial phytase supplementation on growth performance, tibia ash, plasma parameters, apparent ileal digestibility (AID) of amino acid (AA) and apparent digestibility of nutrients in Youxian Sheldrakes fed with low-phosphorus (P) cornsoybean diets. Methods: A total of 350 Youxian Sheldrakes (7d old) were randomly divided into 5 treatment groups: positive control (PC) group has adequate available P diet (0.42% and 0.38%, starter and grower), negative control (NC) group were deficient in available P (0.32% and 0.28%, starter and grower) and NC diet was supplemented with 3 levels of microbial phytase (500, 750, and 1,000 U/kg). Results: Dietary supplementation of phytase in NC diet improved the average daily gain, increased the levels of serum calcium (Ca), tibia Ca and P, AID of AA and apparent digestibility of energy and Ca in starter stage (p<0.05). There was an increased (p<0.001) in the utilization of P from 17.3% to 23.9%. Phytase supplementation (1,000 U/kg) has shown that the AID of His, Thr, Val, indispensable AA, Glu, Pro, and dispensable AA was higher (p<0.05) than that of NC. Moreover, phytase supplementation improved (p<0.05) serum and tibia Ca and P, AID of AA and apparent digestibility of dry matter, crude protein, energy, P and Ca, and reduced (p<0.05) feed to gain ratio (F/G) and the levels of serum alkaline phosphatase in grower stage. Likewise, an increase (p<0.001) in the utilization of P was noticed from 12.6% to 17.2%. Supplement phytase at 750 U/kg improved the AID of His, Thr, Asp, Cys, Pro, and Ser (p<0.05). Conclusion: The microbial phytase supplement could improve growth performance, AID of some AA and apparent utilization of other nutrients in Youxian Sheldrakes, and reduce excreta P load to environment.

Four Species of Jumping Spiders (Areaneae: Salticidae) from China

  • Xian-Jin Peng;Joo-Pil Kim
    • Animal cells and systems
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    • v.2 no.4
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    • pp.411-414
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    • 1998
  • One novel species, Phaeacius yunnanensis n. sp. and three species new to China, Brettus albolimbattus, Hyllus lacertosus and Ptocasius kinhi of the jumping spider.belonging to the family Salticidae, are described based on the materials collected from Yunnan Province, China. The new species is similar to Phaecius lancerarius, but can be distinguished by secondary conductor covers on the emblus. That of the latter below the emblous, retro1aterial tibial apophysis, is much more slender and with an abdominal pattern.

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Associations of IL-10 Gene Polymorphisms with Acute Myeloid Leukemia in Hunan, China

  • Yao, Chen-Jiao;Du, Wei;Chen, Hai-Bing;Xiao, Sheng;Wang, Cheng-Hong;Fan, Zi-Li
    • Asian Pacific Journal of Cancer Prevention
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    • v.14 no.4
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    • pp.2439-2442
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    • 2013
  • We investigated the possible association of interleukin-10 (IL-10) single nucleotide polymorphisms (SNPs) and susceptibility to acute myeloid leukemia (AML) in 115 patients and 137 healthy controls. Genetic analysis of IL-10 SNPs at -819 and -592 was carried out with the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) approach. The IL-10 mRNA expression of AML patients and controls with different genotype was detected by real-time quantitative polymerase chain reaction (RT-PCR). Genetic analysis of IL-10 revealed that the -819AA genotype frequencies and the -819A allele frequencies in the AML group were higher than in the controls (59.1% vs 40.9%; 75.6% vs 63.9%, respectively); there were remarkable differences in -819T/C and -592A/C gene distribution (P<0.05) and the TA haploid frequencies were higher in the AML group (75.6% vs 63.9%, P<0.05). IL-10 mRNA expression in incipient AML patients was obvious higher than the non-tumor group and the remission group ($7.78{\times}10^{-3}$ vs $2.43{\times}10^{-3}$, $3.64{\times}10^{-3}$, P<0.05).The study suggested that the haploid TA and genotype TA/TA may be associated with AML in Han people in Hunan province.The IL-10 SNPs at -819 and -592 sites were associated with AML and may affect IL-10 mRNA expression in AML patients.